Semiconductor power devices have conventionally become the focus of attention, which are mainly used for systems in various power electronics fields such as motor control systems and power conversion systems.
As semiconductor power devices of this type, SiC semiconductor devices having a trench-gate structure have been proposed, for example.
For example, Patent Document 1 discloses a field effect transistor including an n+-type SiC substrate, an n−-type epitaxial layer (drift region) formed on the SiC substrate, a p-type body region formed in a surficial portion of the epitaxial layer, an n+-type source region formed in a surficial portion within the body region, a gate trench formed in a manner penetrating through the source region and the body region to reach the drift region, a gate insulating film formed on the inner surface of the gate trench, and a gate electrode embedded in the gate trench.